Tissue changes in enlarged sternal bursas of turkeys.

Enlarged sternal bursas evident in turkeys beyond 12 weeks of age were examined grossly and microscopically in 169 turkeys 3 to 26 weeks old. Grossly, the enlarged sternal bursas were sacs of varied size and wall thickness containing fluid in amounts from a fraction of a milliliter up to 70 ml. The fluid was usually the consistency of serum but was sometimes viscid, and in infected bursas it would be purulent. Its color varied from amber to red to dark brown depending on the amounts of and the changes in the blood pigments. The synovial membranes were smooth and glistening and of variable thicknesses. Strands or cords of the synovial membrane of variable thickness and number extended from side to side of the sac. Microscopically, the synovial membrane was focally thickened in the small bursas and generally thickened in the larger bursas. The thickening was the result of an increase in the very cellular fibrous tissue and in the number and size of blood vessels. The lining cells were flat fibrocytes one cell thick in the smaller bursas, and round stratified cells in the larger bursas. In infected bursas, mononuclear and heterophilic infiltration occurred. Hemorrhaging occurred quite often, the result of trauma to the highly vascular synovial membrane.     

Defense gene expression patterns of three SAR-induced tomato cultivars in the field

Plant activation is an appealing disease management tool, avoiding some of the challenges of traditional chemical control by not directly impacting the pathogen. This study examined effects of acibenzolar-S-methyl (ASM), a plant activator that induces systemic acquired resistance, on defense response activation in three field-grown tomato cultivars in New York. Salicylic acid, ethylene and jasmonic acid-mediated responses were monitored by following expression of a marker gene for each signaling pathway using quantitative real-time PCR over the course of two ASM applications. ASM induced salicylic acid and ethylene, but not jasmonic acid-regulated gene expression in all cultivars tested. All three cultivars demonstrated a significantly stronger gene expression response relative to the untreated control following the second ASM application. Implications of these findings on management practices are discussed.     

The effect of cow''s dietary copper intake, sire breed, age on her copper status and that of her fetus in the first ninety days of gestation.

The liver copper concentration of the bovine fetus and the hepatic and plasma copper concentrations of its dam during the first trimester of pregnancy were studied. The effect of the dam's dietary copper intake, age, sire breed and stage of pregnancy on her copper status and that of her fetus was also investigated. Simmental sired heifers had the lowest plasma copper concentration. The younger cows (two, three and four years) had significantly lower liver copper concentration than the older cows (six and seven years). The bovine fetal liver copper concentration was approximately 3.1 mmol/g DM and was not affected by dam's age, breed, stage of pregnancy, or copper status.     

Effects on cattle and their calves of tansy ragwort (Senecio jacobaea) fed in early gestation

Tansy ragwort (Senecio jacobaea) fed to pregnant cows on gestation days 15 through 30 in lethal and near-lethal doses did not cause detectable damage to 100-day-old or to full-term fetuses as determined by gross examinations, serum enzyme tests chosen to detect hepatic changes, and by histopathologic examinations. Some cows that appeared normal during gestation expired soon after parturition from typical seneciosis apparently triggered by parturition stress. Pregnant cows fed 12% smaller tansy ragwort doses on gestation days 30 through 45 had only minimal serum enzyme changes and gave birth to normal calves that had normal serum enzymes up to 64 days after parturition.     

An investigation of enzootic Glasser's disease in a specific-pathogen-free grower-finisher facility using restriction endonuclease analysis

Enzootic Glassers's disease was investigated to study the epidemiology of the disease strains on a farm where it presented a problem. Restriction endonuclease fingerprinting (REF) analysis technique was used, as all strains of Haemophilus parasuis are biochemically similar and many strains are biochemically untypable. After young weaned pigs were moved from farm A to farm B, Glasser's disease routinely occurred despite the use of antibiotics and a commercial bacterin. Isolates were taken from the nasal passages and from carcasses of clinically affected cases and subjected to REF analysis. Haemophilus parasuis was not isolated from any of the pigs on farm A, but it was isolated from 7/10 and 5/10 nasal swabs taken from farm B. Two H. parasuis strains isolated from clinical cases of Glasser's disease from farm B had an identical REF pattern, but were different from the nasal swabs and the H. parasuis strain contained in the bacterin. The subsequent use of a custom autogenous bacterin made from a clinical isolate of H. parasuis reduced the mortality rate on farm B. This investigation indicates that nasal isolates of H. parasuis are different than those causing clinical disease, and not all bacterin strains are cross protective for other strains.     

A descriptive study of the frequency and characteristics of proliferative enteropathy in swine in Ontario by analyzing routine animal health surveillance data

Routine surveillance data, collected on pathology submissions at the Animal Health Laboratory in Guelph between 1992 and 1997, were analyzed to determine demographic, clinical, and pathologic characteristics of cases of proliferative enteropathy and the frequency of this condition relative to other infectious enteric diseases in swine in Ontario. The most commonly reported disease was Escherichia coli enteritis (average cases/year = 70.0). Among infectious enteropathies that occur typically in neonatal pigs, coccidiosis (28.4 cases/year) and rotaviral enteritis (5.6 cases/year) were reported. Among infectious enteropathies generally associated with diarrhea in weaner and grower/finisher pigs, the most frequently reported was proliferative enteropathy (27.6 cases/year), followed by swine dysentery (23.3 cases/year), transmissible gastroenteritis (19.6 cases/year), and salmonellosis (8.4 cases/year). Diarrhea and bloody diarrhea were reported in 29% and 31%, respectively, of herds diagnosed with proliferative enteropathy. Important gross intestinal lesions included mucosal hypertrophy (62% of cases), hemorrhage (47%), and mucosal necrosis (34%). Histologic intestinal lesions included epithelial hyperplasia (90% of cases), mucosal necrosis (59%), and inflammation (49%). Our results suggest that proliferative enteropathy is a major infectious enteric disease in grower/finisher pigs in Ontario.